Anxiety disorders are often debilitating chronic conditions, which can be present from an early age or begin suddenly after a triggering event. They are prone to flare up at times of high stress. Anxiety disorders include panic disorder, agoraphobia, social anxiety disorder (also known as social phobia), specific phobia, or simple phobia, generalized anxiety disorder, obsessive-compulsive disorder, and post-traumatic stress disorder.
Many of these disorders can be treated with the aid of counseling and behavioral therapies, such as cognitive therapy. Such treatments may be used with or without adjunctive pharmaceutical therapy. A number of drugs have been used to treat these disorders, including benzodiazepines and antidepressants of all main classes: selective serotonin reuptake inhibitors (“SSRIs”), tricyclic antidepressants (“TCAs”), and monoamine oxidase inhibitors (“MAOIs”).
Obsessive Compulsive Disorder (“OCD”) is an example of an anxiety disorder. It is a debilitating psychiatric condition with a lifetime prevalence of 2-3%. It is characterized by recurrent, intrusive thoughts (obsessions) and/or repetitive, stereotyped behaviors (compulsions) that last for at least one hour per day and significantly interfere with an individual's normal level of functioning. Although cognitive behavioral therapy and pharmacotherapy with serotonin reuptake inhibitors (SRI) are effective treatments for many patients, a subset experience minimal relief from their symptoms with these standard treatments. When severe, OCD is completely incapacitating with devastating consequences for patients and their families. Augmentation strategies with neuroleptic medications can improve the effectiveness of SRI therapy but do not eliminate OCD symptoms (Saxena et al., J. Clin. Psychiatry, 57:303-6, 1996; McDougle et al., J. Clin. Psychiatry, 56:526-8, 1995) and are associated with adverse effects when used chronically. Consequently, improved pharmacological treatments are needed. The clinical observation that few patients experience a complete response to SRI's or dopamine antagonists suggests that other neurochemical systems are involved in the pathophysiology of OCD.
Thus, there is a need for pharmaceutical therapies that can be used to treat patients with the above disorders, including patients who do not respond to currently available therapies, as well as for pharmaceutical therapies that improve the efficacy of currently available treatment regimens.